As time went on it grew to be customary, instead of rendering services for the use of the land held by copyhold, to pay a money rent. In other words, the system of leasing the little farms came into use, and from that came the tenant farmer. This left the other laborers about the lord's demesne or his castle as before. While the class of villeins, who did only occasional services, although definite as to amount and time, gradually commuted these services into money payments, and became farmers, the other serfs still remained on the manor, liable to do their work when and where it was customary. This rise of the wealthier tenants made a new class between the large proprietors, the lords of the manor, and the tenants or serfs still bound by custom to work for their lords. But the same process which freed the farmer from personal service in time became the chief way of freeing the serf also. Until this came about the serf or laborer, whatever other rights he might have, and he was not a slave, was born to his holding and his lord. He could choose neither master nor place of work. "He paid head money for license to remove from the estate in search of trade or hire, and a refusal to return on recall by his owner would have ended in his pursuit as a fugitive outlaw." But the advance of society silently worked to free the laborer from this local bondage. The runaway serf gained freedom by residence in a chartered town for a year and a day. The influence of the church was directed toward his emancipation, at least on all estates outside of its own, but the main cause was the growing tendency to commute labor services for money payments. As Mr. Green says: "The luxury of the castle hall, the splendor and pomp of chivalry, the cost of campaigns, drained the purses of knight and baron, and the sale of freedom to a serf or exemption from services to a villein afforded an easy and tempting mode of refilling them. In this process even kings took part. Edward III sent commissioners to royal estates for the especial purpose of selling manumissions to the king's serfs, and we still possess the names of those who were enfranchised with their families by a payment of hard cash in aid of the exhausted exchequer." The Crusades, whatever else they may have accomplished, aided in this freedom for the serf. Those costly expeditions dissipated the estates of the barons, and, to use Hume's somewhat strained expression, "Their poverty extorted from their pride those charters of freedom which unlocked the fetters of the slave." And so, following the rise of the farmer, came this new class--the free laborer. By the latter part of the fourteenth century labor was no longer, as a rule, "bound to one spot or one master; it was free to hire itself to what employer and to choose what field of employment it would."